The Scythe Mugen-2 features design improvements, ships with a 120mm PWM fan, and mounts using a simple bolt-thru installation procedure – a first for Scythe. Multiple fans can also be accommodated. With two fans, quiet cooling performance is simply amazing.
July 15, 2009 by Lawrence Lee
| Product | Scythe Mugen-2 CPU Cooler |
| Manufacturer | Scythe |
| Street Price | US$35~$40 |
The Scythe Mugen-2 is the updated version of the
Mugen (AKA Infinity) CPU cooler. At the time of its release, the Mugen
was an excellent heatsink, able to cool most of the processors of its day with
little airflow. Unfortunately the Mugen coexisted with the better performing Scythe
Ninja, which took most of accolades. The heatsink itself has had some interesting design improvements and now comes with a 120mm PWM fan. Most importantly, this big heatsink sports a simple
bolt-thru installation procedure. It is Scythe’s first serious departure from stock Intel plastic push-pins in many years.
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While Scythe practically invented the massive CPU heatsink, most of them use
stock LGA775 pushpin and AMD tension-clip mounts. These mounting methods are fine for
regular-sized coolers, but peace of mind quickly goes out the window in the
face of gravity acting on a 15-16cm tall aluminum/copper tower weighing almost
1kg and sitting on a processor worth hundreds of dollars. With the Mugen-2, installation
on any of the compatible sockets requires the heatsink to be bolted down with steel machined screws to a spider-like steel backplate. This is a major improvement over plastic push-pins and stock mounting clips.
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| Scythe Mugen-2: Key Features (from the product web page) | |
| Feature & Brief | Our Comment |
| F.M.S.B. (Flip Mount Super Back-Plate) The newly developed F.M.S.B. (Flip Mount Super Back-Plate) both improves the compatibility and mounting of the cooler with the motherboard. With this system, a solution was developed which is not using push pins but is instead based on a Back Plate/screws mounting set. Of course, Mugen-2 is compatible with all the current sockets, including the new Intel Socket LGA1366. | The Mugen-2 is the first Scythe CPU cooler to feature a straight bolt-thru mounting design. A single backplate offers hard mounting for all modern Intel and AMD sockets. |
| Multi Fan Mount Structure As with the former Mugen it is possible to mount the supplied fan in four different directions. By this, the user can arrange the air flow to the circumstances of his deployment area. Furthermore, a maximum of 4 fans be installed, the needed fan clips have to be bought separately. | Like the Ninja series, fans can be installed on all or any of the four sides. The Mugen-2 is not a perfectly square heatsink, though, so fans placed on the narrow sides will not perform as well. |
| M.A.P.S. (Multiple Airflow Pass-Through Structure) The newly developed M.A.P.S. (Multiple Airflow pass-through structure) is a completely new lamellar structure, where the airflow generated by the Scythe Slip Stream 120 mm PWM fan can be used perfectly | Mugen-2 has a series of slits running down the length of its mass, effectively splitting the fins in into five columns. This feature has been implemented to reduce resistance to airflow. |
| Scythe Mugen-2: Specifications (from the product web page) | |
| Model Name: | MUGEN-2 |
| Model #: | SCMG-2000 |
| Manufacturer: | Scythe Co., Ltd. Japan |
| Heatsink | |
| Dimension: | 130 x 100 x 158 mm 51.2 x 39.4 x 62.2 inch |
| Weight: | 870 g, 30.7 lb |
| Baseplate-Material: | Nickle-plated copper |
| Compatibility | IntelLGA1366 IntelLGA775 (SocketT) Intel Socket 478 Processor AMD Socket AM2+ AMD Socket 940 Processor AMD Socket 939 Processor AMD Socket 754 Processor |
| Fan | |
| Dimension: | 120 x 120 x 25 mm 4 3/4 x 4 3/4 x 1 inch |
| Weight: | 115 g, 0.25 lb |
| Speed: | 324 ~ 1,200 rpm (±10%) PWM Function |
| Noise Level: | 0 – 26.50 dBA |
| Air Flow: | 0 – 74.25 CFM, 0 – 126 m³/h |
| Bearing: | Sleeve |
PHYSICAL DETAILS
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INSTALLATION
The most critical aspect of installation is for the heatsink
to be securely mounted. The more firmly it is installed, the better the contact
between the heatsink’s base and the CPU itself. It’s also less likely to fall
off. Ease of installation is also important — a simple mounting scheme
means less time spent installing, and a reduced likelihood of screwing up.
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TESTING
Before thermal testing, we took some basic physical measurements.
| Scythe Mugen-2: Approximate Physical Measurements | |
| Weight | 740 g 850 g with fan and clips 870 g with fan, clips and topside mounting hardware |
| Fin thickness | 0.31 mm |
| Fin spacing | 1.89 mm |
| Vertical Clearance | 48 mm (measured from the motherboard PCB to the heatsink’s bottom fin) |
| Horizontal Overhang | N/A (measured from the edge of the heatsink to the top edge of our test motherboard’s PCB) |
| Comparison: Approximate Fin Thickness & Spacing | ||
| Heatsink | Fin Thickness | Fin Spacing |
| Scythe Ninja 2 | 0.39 mm | 3.68 mm |
| Thermalright HR-01 Plus | 0.45 mm | 3.15 mm |
| Noctua NH-U12P | 0.44 mm | 2.63 mm |
| Thermolab Baram | 0.44 mm | 2.52 mm |
| Prolimatech Megahalems | 0.50 mm | 2.00 mm |
| Xigmatek HDT-S1283 | 0.33 mm | 1.96 mm |
| Scythe Mugen-2 | 0.31 mm | 1.89 mm |
| Zerotherm Zen FZ120 | 0.37 mm | 1.80 mm |
| Zalman CNPS10X Extreme | 0.42 mm | 1.50 mm |
| Thermalright Ultra-120 | 0.45 mm | 1.42 mm |
Testing was done according to our
unique heatsink testing methodology, and the included fan was profiled
using our standard fan testing
methodology. A quick summary of the components, tools, and procedures
follows below.
Key Components in Heatsink Test Platform
- Intel
Pentium D 950 Presler core, C1 stepping. TDP of 95W; under our test
load, it measures 78W including losses in the VRMs. - Asus P5Q-EM motherboard.
A microATX board with integrated graphics and short solid-state capacitors
around the CPU socket, and a diminutive northbridge heatsink for maximum compatibility. - Intel
X25-M 80GB 2.5″ solid-state drive. - 1GB
of Corsair XMS2 DDR2 memory. 2 x 512MB PC2-8500. - FSP Zen 300W
fanless power supply. - Arctic Silver
Lumière: Special fast-curing thermal interface material, designed
specifically for test labs. - Nexus 120 fan (part of our standard testing methodology; used when
possible with heatsinks that fit 120x25mm fans)
| Nexus 120mm fan measurements | ||
| Voltage | Noise | RPM |
| 12V | 16 dBA@1m | 1100 RPM |
| 9V | 13 dBA@1m | 890 RPM |
| 7V | 12 dBA@1m | 720 RPM |
| 5V | 11 dBA@1m | 530 RPM |
Measurement and Analysis Tools
- Seasonic
Power Angel for measuring AC power at the wall to ensure that the
heat output remains consistent. - Custom-built, four-channel variable DC power supply, used to regulate
the fan speed during the test. - PC-based spectrum analyzer:
SpectraPlus with ACO Pacific mic and M-Audio digital
audio interfaces. - Anechoic chamber
with ambient level of 11 dBA or lower - Various other tools for testing fans, as documented in our
standard fan testing methodology. - SpeedFan, used to monitor the on-chip thermal sensor. This sensor is not
calibrated, so results are not universally applicable. - CPUBurn
P6, used to stress the CPU heavily, generating more heat than most
real applications. Two instances are used to ensure that both cores are stressed. - Throttlewatch
2.01, used to monitor the throttling feature of the CPU to determine
when overheating occurs.
Load testing was accomplished using CPUBurn to stress the processor, and the
graph function in SpeedFan was used to make sure that the load temperature was
stable for at least ten minutes. The stock fan was tested at various voltages
to represent a good cross-section of its airflow and noise performance.
TEST RESULTS
Stock Fan Testing
The stock fan is a PWM version of the SY1225SL12M from the acclaimed Slip Stream
series. We’ve been waiting a long time for Scythe to begin shipping their heatsinks
with PWM fans and it looks like they’re finally starting to make the transition.
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| Stock Fan Specifications | |||
| Manufacturer | Scythe | Power Rating | 2.16 W |
| Model | SY1225SL12LM-P | Airflow Rating | 74.25 CFM |
| Bearing Type | Sleeve | RPM Rating | 1200 |
| Frame Size | 120 x 120 x 25 mm | Noise Rating | 26.5 dBA |
| Hub Size | 1.41″ (35.9 mm) | Header Type | 4-pin PWM |
| Weight | 110 grams | Starting Voltage | ~5V |
| The data in the green cells is provided by the manufacturer; we measured the data cited in the blue cells | |||
Like many other PWM fans, the fan speeds drop off very quickly when the voltage
is decreased. We typically test fans at 12V, 9V, 7V, and 5V, but this particular
fan becomes inaudible in our anechoic chamber at only 8V, so we adjusted our
levels appropriately. The fan speeds at 12V, 10V, 9V, and 8V differ by 200-300
RPM, offering a broad range for testing.
| Fan Measurements | ||
| Voltage | Noise Level | Speed |
| 12V | 24 dBA | 1340 RPM |
| 10V | 15 dBA | 1020 RPM |
| 9V | 12 dBA | 790 RPM |
| 8V | 11 dBA | 500 RPM |
Fan @ 12V: The fan produces mostly turbulent noise with a bit of a low-pitched
drone.Fan @ 10V: At this level, the noise drops significantly from 24 dBA@1m
to 15 dBA@1m. The acoustics are excellent with only a small amount of benign
turbulence.Fan @ 9V: The fan sounds smooth as silk, with almost no bearing noise.
At 9V the noise characteristics rival that of the Nexus fan.Fan @ 8V: Inaudible at one meter’s distance.
Overall the fan is excellent just like previous Slip Streams. As far as stock
fans go, it is one of the best acoustically.
Cooling Results
| Scythe Mugen-2 w/ stock fan | ||||
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| Fan Voltage | SPL@1m | Temp | °C Rise | °C/W |
| 12V | 24 dBA | 33°C | 12 | 0.15 |
| 10V | 15 dBA | 35°C | 14 | 0.18 |
| 9V | 12 dBA | 38°C | 17 | 0.22 |
| 8V | 11 dBA | 45°C | 24 | 0.31 |
| Scythe Mugen-2 w/ reference 120mm fan | ||||
| 12V | 16 dBA | 36°C | 15 | 0.19 |
| 9V | 13 dBA | 38°C | 17 | 0.22 |
| 7V | 12 dBA | 40°C | 19 | 0.24 |
| 5V | 11 dBA | 44°C | 23 | 0.29 |
| Load Temp: CPUBurn for ~10 mins. °C Rise: Temperature rise above ambient (21°C) at load. °C/W: based on the amount of heat dissipated by the CPU (measured 78W); lower is better. | ||||
The Scythe Mugen-2 performed very well, though suffered noticeably when the
fan speed was lowered to about 500 RPM. At 12V the CPU temperature was 12°C
above ambient, putting it in league with some of today’s top heatsinks. The
temperature increased by 2°C at 10V but was accompanied by a sizable decrease
in noise — it is fairly quiet and unobtrusive at this level. At 9V, performance
degraded by an additional 3°C, and then another 7°C at 8V. The noise
the fan generates between 9V and 8V (800~500 RPM) is inaudible unless the environment is almost
completely silent.
The stock fan fared well against our reference Nexus fan, an admirable feat.
At similar noise levels, the two fans performed within 2°C of one another.
There is really no reason whatsoever to consider replacing the included fan.
Cooling Results – Two Fan Configuration
Resistance to airflow is higher the closer the fins are to one another, and
the wider heatsink, the further air has to travel to cool it effectively. The
Mugen-2 is wider than most at 100 mm wide and its fins are tightly-spaced, making
it a good candidate for two fans in a push-pull configuration.
| Scythe Mugen-2 w/ reference 120mm fan | ||||
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| Fan Voltage | SPL@1m | Temp | °C Rise | °C/W |
| 12V | 16 dBA | 36°C | 15 | 0.19 |
| 9V | 13 dBA | 38°C | 17 | 0.22 |
| 7V | 12 dBA | 40°C | 19 | 0.24 |
| 5V | 11 dBA | 44°C | 23 | 0.29 |
| Scythe Mugen-2 w/ Two reference 120mm fans | ||||
| 12V | 20 dBA | 32°C | 11 | 0.14 |
| 9V | 14~15 dBA | 33°C | 12 | 0.15 |
| 7V | 12 dBA | 34°C | 13 | 0.17 |
| 5V | 11 dBA | 38°C | 16 | 0.21 |
| Load Temp: CPUBurn for ~10 mins. °C Rise: Temperature rise above ambient (21°C) at load. °C/W: based on the amount of heat dissipated by the CPU (measured 78W); lower is better. | ||||
With two of our reference fans in a push-pull configuration running at 12V,
the Mugen-2 exhibited only a minor 4°C improvement while increasing the
noise level by 4 dBA. As the fan speeds were lowered, the improvement increased
— two fans seem particularly fit for use at low fan speeds. At 9V, the
two fan setup was 1~2 dBA louder and 5°C cooler than one fan. At 7V and
5V, there was no measurable increase in noise using dual fans, and the CPU temperature
was improved by 6°C and 7°C, respectively.
Comparables
| °C rise Comparison: The Best of the Best | ||||
| Heatsink | Nexus 120mm fan voltage / SPL @1m | |||
| 12V | 9V | 7V | 5V | |
| 16 dBA | 13 dBA | 12 dBA | 11 dBA | |
| Prolimatech Megahalems | 10 | 14 | 17 | 20 |
| Thermalright U120E | 12 | 14 | 17 | 24 |
| Thermalright HR-01+ | 13 | 15 | 16 | 20 |
| Xigmatek HDT-S1283 | 13 | 15 | 18 | 22 |
| Noctua NH-U12P | 14 | 16 | 17 | 21 |
| Zalman CNPS10X Extreme | 14 | 17 | 21 | 26 |
| Zerotherm Zen FZ120 | 15 | 16 | 19 | 24 |
| Scythe Mugen-2 | 15 | 17 | 19 | 23 |
| Scythe Ninja 2 | 17 | 18 | 20 | 23 |
| Thermolab Baram | 18 | 20 | 22 | 25 |
| Scythe Mugen-2 w/ Two reference 120mm fans | ||||
| Scythe Mugen-2 | 11 | n/a | 13 | 16 |
The Mugen-2 managed a slight performance increase over the Ninja 2. It’s a solid
heatsink, but used as delivered. it doesn’t cool quite well enough to be called elite. As the fan speed is decreased, its relative position improves and it manages to get within 2-3°C of the Thermalright
HR-01+, even though the Mugen’s fin spacing is tighter than most of
the competition.
Where the Mugen-2 really shines is when a second quiet fan is added in a push-pull configuration. With both fans set to spin ~700rpm or lower, there is essentially no noise increase compared to just one fan, but the cooling performance moves up to levels never achieved in the past. A temperature rise of just 16°C at a noise level of 11 dBA@1m is simply astonishing performance.
MP3 SOUND RECORDINGS
These recordings were made with a high
resolution, lab quality, digital recording system inside SPCR’s
own 11 dBA ambient anechoic chamber, then converted to LAME 128kbps
encoded MP3s. We’ve listened long and hard to ensure there is no audible degradation
from the original WAV files to these MP3s. They represent a quick snapshot of
what we heard during the review.
These recordings are intended to give you an idea of how the product sounds
in actual use — one meter is a reasonable typical distance between a computer
or computer component and your ear. The recording contains stretches of ambient
noise that you can use to judge the relative loudness of the subject. Be aware
that very quiet subjects may not be audible — if we couldn’t hear it from
one meter, chances are we couldn’t record it either!
The recording starts with 10 second segments of room ambiance, then the fan
at various levels. For the most realistic results, set the volume so that
the starting ambient level is just barely audible, then don’t change the volume
setting again.
- Scythe
Mugen-2 with stock Scythe fan at one meter
— 8V (11 dBA@1m)
— 9V (12 dBA@1m)
— 10V (15 dBA@1m)
— 12V (24 dBA@1m)
- Scythe
Mugen-2 with two reference Nexus fans at one meter
— 7V (12 dBA@1m)
— 9V (14~15 dBA@1m)
— 12V (20 dBA@1m)
FINAL THOUGHTS
Scythe Mugen-2’s bolt-thru mounting has been long
awaited by PC enthusiasts everywhere. We are not completely enthusiastic about how the bolt-through mounting was implemented — applying a screwdriver
to the back side of a motherboard is tedious and possibly dangerous.
Still, it is a much better alternative to plastic pushpins, especially for a large cooler
like the Mugen-2. Hard mounting ensures good contact between the cooler’s base
and the CPU, and the heatspreader helps prevent the PCB from bending. It also ensures consistency from one installation to another; if the instructions are followed correctly, every user should achieve the same tight installation.
Shipping the
heatsink with a good quality PWM fan is an excellent move. Many users have motherboards
with fan controllers that only work with PWM fans, so for them this is a welcome
addition. Adding PWM functionality hasn’t dulled the shine of the smooth-sounding
Slip Stream fan.
The Mugen-2’s stock performance was slightly disappointing considering its substantial
cooling surface area. It flirted with elite silent cooler status but did not quite break through to the
upper echelon.
Where the Mugen-2 really shines is in a two-fan push-pull configuration.
The improvement in cooling was especially notable at
low fan speeds (read: in silent operation). With two of our reference Nexus fans running at 7V and 5V, the
CPU temperature improved by 6°C and 7°C respectively. Better still,
at 7V and below, the addition of the second reference fan did not result in
any measurable increase in noise level.
The Mugen-2 currently retails for US$35~$40, putting it in competition with direct-touch
heatpipe coolers from Xigmatek, Kingwin, and others. It may not perform quite
as well as the HDT-S1283,
but it does hold several key advantages: It has a more secure mounting
system, allows for “proper” orientation on AMD motherboards, and it ships with a superior fan. We’re guessing that the stock PWM fan will soon be availble for separate purchase, and hopefully, priced similarly to the $10 for the original Slipstream series. The end price of $50 for silent cooling performance of this caliber would be an absolute steal.
| Scythe Mugen-2 | |
| PROS * Excellent single fan performance | CONS * Iinstallation a bit awkward |
Our thanks to Scythe
for the Mugen-2 heatsink sample.
SPCR Editor’s Choice Award
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